Evaluation of Confinement Effect of High Strength Concrete Confined with Transverse Ties in Reinforced Concrete Columns

An experimental study was conducted to investigate the confined effects by transverse reinforcements in reinforced high strength concrete tied columns subjected to monotonically increasing concentric axial compression. Fifteen large scale columns (260 ??? × 260 ??? × 1200 ???) used high strength concrete of 85 MPa were fabricated to simulate similarly an actual structural members size. Effects of main variables such as the volumetric ratios, spacing, configurations, and yield strength of transverse reinforcement were studied in this research program. Especially, various types of transverse reinforcement were considered in this experimental study. Test results indicated that gains of strength and ductility of confined high-strength concrete in tied columns could be increased, if efficient arrangements, configurations and volumetric ratios of transverse reinforcements were provided. And an improvement of strength and ductility for the confined high strength concrete is proportional to the effective lateral pressure of transverse reinforcement